Thank you! From your perspective does the 2cm hold up as nicely? I’m concerned about longevity and not wanting to have to repair/replace these new countertops for a very long time. My apologies if these are bad questions.

If I got 2cm, I wouldn't build up the edge and risk a lamination line. I'd just get 3cm. 2cm is plenty strong enough for countertops, just make sure your cabinet installer knew you weren't going to build up the edge or you may have trouble with appliances fitting properly.

Quartz at 20mm is way stronger under compression and tensile strength than any granite.

20mm is fine for any countertop use.